This invention broadly relates to a method of controlling traffic between ATM (Asynchronous Transfer Mode) exchanges in an ATM network having a plurality of terminals connected via the ATM exchanges, and in particular, to a method of effectively utilizing transmission paths of the ATM network.
In case where a transmission terminal communicates with another terminal via an ATM network connected to ATM exchanges, amount of transmission (traffic) is controlled between the transmission terminal and the ATM exchange. In general, the transmission terminal subscribes traffic bands to be used, and the ATM exchange controls so that the transmission terminal uses a transmission path within the transmission bands. The traffic bands are fixed to the bands at the time of subscription.
Under such circumstances, the ATM exchange includes a CAC (Connection Admission Controller) and a UPC (Usage Parameter Controller). With this structure, the CAC judges whether or not a band is held within the subscription bands of the transmission path connected to the UPC as well as whether or not the ATM exchange can be connected to the ATM network (in other words, whether it is a usable band or not). Therefore, the availability of the band depends on a traffic state of the ATM network at that time.